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6loWPAN: IEEE802.15.4 MAC driver will need a special form of the network device structure to manage fragmentation of the large packet into frames.

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This commit is contained in:
Gregory Nutt
2017-03-29 10:17:34 -06:00
parent eb344d7260
commit 5fb222180c
5 changed files with 85 additions and 39 deletions
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include/nuttx/net/sixlowpan.h
+49 -31
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@@ -50,8 +50,11 @@
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <nuttx/net/netdev.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
@@ -223,51 +226,66 @@
(((a)->u16[6]) == 0) && \
(((a)->u8[14]) == 0))
/* Maximum size of an IEEE802.15.4 frame */
/* This maximum size of an IEEE802.15.4 frame. Certain, non-standard
* devices may exceed this value, however.
*/
#define SIXLOWPAN_MAC_MAXFRAME 127
#define SIXLOWPAN_MAC_STDFRAME 127
/****************************************************************************
* Public Types
****************************************************************************/
/* The header for fragments
/* The device structure for IEEE802.15.4 MAC network device differs from the
* standard Ethernet MAC device structure. The main reason for this
* difference is that fragmentation must be supported.
*
* NOTE: We do not define different structures for FRAG1 and FRAGN headers,
* which are different. For FRAG1, the offset field is just not used
* The IEEE802.15.4 MAC does not use the d_buf packet buffer directly.
* Rather, it uses a smaller frame buffer. The packet data is provided to
* the frame buffer each time that the IEEE802.15.4 MAC needs to send
* more data.
*
* This is accomplished by "inheriting" the standard 'struct net_driver_s'
* and appending the frame buffer as well as other metadata needed to
* manage the fragmentation. 'struct ieee802154_driver_s' is cast
* compatible with 'struct net_driver_s' when CONFIG_NET_MULTINIC is not
* defined or when dev->d_lltype == NET_LL_IEEE802154.
*/
struct sixlowpan_frag_hdr
struct ieee802154_driver_s
{
uint16_t dispatch_size;
uint16_t tag;
uint8_t offset;
};
/* This definitiona must appear first in the structure definition to
* assure cast compatibility.
*/
/* The HC1 header when HC_UDP is not used
*
* When all fields are compressed and HC_UDP is not used, we use this
* structure. If HC_UDP is used, the ttl is in another spot, and we use the
* sixlowpan_hc1_hc_udp structure
*/
struct net_driver_s i_dev;
struct sixlowpan_hc1hdr_s
{
uint8_t dispatch;
uint8_t encoding;
uint8_t ttl;
};
/* IEEE802.15.4 MAC-specific definitions follow. */
/* HC1 followed by HC_UDP */
/* The i_frame array is used to hold outgoing frame. When the
* IEEE802.15.4 device polls for new data, the outgoing frame containing
* the next fragment is placed in i_frame.
*
* The network will handle only a single outgong frame at a time. The
* IEEE802.15.4 MAC driver design may be concurrently sending and
* requesting new framesusing break-off fram buffers. That frame buffer
* management must be controlled by the IEEE802.15.4 MAC driver.
*
* Driver provied frame buffers should be 16-bit aligned.
*/
struct sixlowpan_hc1_hcudp_hdr_s
{
uint8_t dispatch;
uint8_t hc1_encoding;
uint8_t hc_udp_encoding;
uint8_t ttl;
uint8_t ports;
uint16_t udpchksum;
FAR uint8_t *i_frame;
/* The length of valid data in the i_frame buffer.
*
* When the network device driver calls the network input function,
* i_framelen should be set to zero. If there is frame to be sent
* by the network, i_framelen will be set to indicate the size of
* frame to be sent. The value zero means that there is no frame
* to be sent.
*/
uint16_t i_framelen;
};
/* The structure of a next header compressor. This compressor is provided